1. Field of the Invention
The present invention generally relates to the field of manufacture and assembly of circuit boards. More specifically it relates to a tape guide for guiding a carrier tape in a component mounting machine, a tape magazine for receiving the tape guide, and a system including the tape guide and the tape magazine.
2. Description of Background Art
Generally, within the field of manufacture and assembly of circuit boards, electronic components are fed to a component mounting machine for mechanically and/or electrically mounting the components onto a circuit board. These surface mounted components are often delivered spaced apart along the length of a component tape, which consists of a lower carrier tape provided with compartments, one for each component, and an upper cover, or cover tape or protective tape. After positioning the electronic components in the corresponding compartments, the cover tape is attached to the carrier tape, and the component tape is wound on a component reel. The attachment of the cover tape to the carrier tape can, for instance, be performed by providing either the cover tape or the carrier tape with adhesive areas, or by fusing the cover tape to the carrier tape. Then, the component reel is transferred to a component mounting machine, which feeds a component to a certain predetermined picking position where it can be picked, or collected, by a pick-up head. WO 86/00778 shows a cassette magazine for a component mounting machine using the above described method.
According to the method conventionally used within the art, the loading of a component tape in a component mounting machine involves the following steps. Placing the component tape reel into the tape holder of a component mounting machine, or into a tape magazine of a component mounting machine; introducing the free end of the component tape into a feeding mechanism, provided in the machine or in the magazine, such that feeding pins engage corresponding holes provided in the component tape; separating, by hand, the end of the cover tape from the end of the carrier tape for a distance sufficient for the cover tape to be engaged with a cover tape handling means; and lowering a locking mechanism over the carrier tape for holding the carrier tape against the feeding mechanism.
Prior to the picking of the components, each component has to be exposed so as to make it available for picking. Conventionally, this is achieved by removing the cover tape from the carrier tape. The cover tape is then fed away by a separate cover tape handling means in order for the cover tape not to disturb the picking of components. Generally, the cover tape handling means comprises a winding hub on which the cover tape is wound. Additionally, when unloading the component tape from the component mounting machine, or the tape magazine, the winding hub has to be cleared of the cover tape.
A considerable length of the end of the cover tape has to be separated from the end of the carrier tape in order to bring the cover tape end to a cover tape handling means. Thus, the first decimeters of a new carrier tape are not provided with components. Otherwise, numerous components would be wasted during loading. However, when reloading a tape reel that already has been partly used, the tape is provided with components throughout, and consequently a large number of components may be wasted.
U.S. Pat. No. 4,820,369 discloses an alternative method and device for exposing the components at the picking position. According to the embodiments shown in FIGS. 7 and 8, the cover tape is separated from the carrier tape along one side of the carrier tape only, while the cover tape remains adhered to the carrier tape along the other side. Thereby, the need for separate cover tape handling means is reduced or even eliminated. Using this method, the distance of cover tape that has to be removed from the carrier tape when loading or reloading a carrier tape can be reduced, but not eliminated, thus there would still be some component waste. Further, there would also still be components wasted when unloading a carrier tape from the compartments where the components have been exposed but have not yet been picked-up. Even though this method would be preferred as compared to using a separate cover tape handling means, the loading of the carrier tape into the component mounting machine and the device for exposing the components must still be performed individually for each carrier tape. During this time, the component mounting machine must be shut off.
As realised from the above, the loading of a component tape in a component mounting machine is a time-consuming and complicated process that has to be performed every time a new component has to be added to the circuit board manufacturing process, and every time an empty component tape has to be replaced. This negatively affects the overall time efficiency of the manufacturing process and, hence, the overall costs. Additionally, when using a winding hub, or the like, for handling the cover tape, the required time for the loading process is further increased, and the unloading of the component tape includes the additional step of clearing the winding hub of the cover tape. Furthermore, there is high risk of a considerable component waste with the loading method according to prior art.
It is therefore an object of the present invention to provide a solution to the problem of complicated and time-consuming loading of a carrier tape into a component mounting machine.
A further object of the present invention is to reduce the high number of wasted components when unloading/reloading a carrier tape from/into a component mounting machine.
This and other objects are achieved according to the present invention by providing a tape guide, a tape magazine and a system having the features defined in the independent claims. Preferred embodiments are defined in the dependent claims.
For the purpose of clarity, the term lateral refers to the lateral direction of the carrier tape. The terms distal and proximal refers to the direction opposite to and along the feeding direction of the carrier tape, respectively.
The present invention is based on the insight of providing a tape guide, for guiding a carrier tape in a component mounting machine, said tape guide comprising exposure means for exposing the components at a picking position, wherein the exposure means comprises separating means for separating and lifting a lateral portion of the cover from the carrier tape, leaving the remaining portion of the cover at least partially attached to the carrier tape, and for bringing the lifted portion of the cover aside, with the ability to be releasably mounted such that the loading and/or unloading of a carrier tape into and from the tape guide can be performed away from the component mounting machine. Preferably, this is achieved according to the present invention by providing a tape guide with locking means for ready and quick attachment and detachment to interacting locking means in a component mounting machine, guiding means for guiding a carrier tape, and carrier tape retaining means for retaining the position of the carrier tape relative the tape guide.
By providing a tape guide with the ability to be loaded with a carrier tape away from a component mounting machine and to be subsequently loaded into the component mounting machine, a facilitated loading of the carrier tape into the machine, a reduced downtime of the machine, and, thereby, an improved time efficiency of the entire manufacturing process is achieved. This is due to the fact that the time-consuming process of loading the carrier tape into a component mounting machine, as described above with reference to known art, is reduced to simply placing a component tape reel into the tape holder of a component mounting machine, and mounting a tape guide into the machine. The rest of the loading process is performed beforehand and away from the component mounting machine. Thus, the downtime of the component mounting machine due to the loading of a carrier tape is limited to the actual time for placing a tape reel into the machine, and for loading a tape guide into the machine, which increases the time efficiency of the machine considerably.
The required features of the tape guide for enabling the loading of a carrier tape away from the machine and the subsequent loading of the tape guide, with the carrier tape, into the machine comprise locking means for ready and quick attachment and detachment of the tape guide into and from the machine, guiding means for correctly guiding the carrier tape into the machine, and carrier tape retaining means for retaining the position of the carrier tape relative the tape guide.
The locking means is provided for ready, quick and accurate mounting of the tape guide into the component mounting machine. The locking means of the tape guide is arranged for interaction with corresponding locking means provided on the component mounting machine, thus providing both a correct positioning and a secure mounting of the tape guide. Preferably, the locking means is in the form of resiliently biased snap-in locking means, e.g. in the form of a latch and a recess provided on the tape guide interacting with axles provided on the component mounting machine, or in the form of a catch and an axle, respectively, provided on the component mounting machine interacting with corresponding protrusion and recess provided on the tape guide. As realised by a person skilled in the art, various types of snap-in locking means, or other sorts of quick couplings, can be used for ready and quick attachment and detachment of the tape guide into and from a component mounting machine.
The guiding means is provided for guiding the carrier tape to the correct position within the component mounting machine, such that the components to be picked by a pick-up head reaches the correct picking position. The guiding means is preferably in the form of opposing grooves extending from the distal end of the tape guide to the proximal end thereof.
According to the invention, the tape guide is provided with means for exposing a component to be picked at a picking position. This exposure means comprises separating means for separating and lifting a lateral portion of the cover from the carrier tape, leaving the remaining portion of the cover at least partially attached to the carrier tape, and for bringing the lifted portion of the cover aside such that the component to be picked can be exposed. A more detailed description of such separating means will follow below.
The use of such separating means eliminates the need for means handling the cover tape after removal from the carrier tape since the cover remains attached to the carrier tape. Thereby, the loading process is even further facilitated and the loading time is reduced, reducing the downtime of the mounting machine and positively effecting the efficiency of the entire manufacturing process.
By arranging the separating means such that it covers a compartment, from the separating and lifting of the lateral portion of the cover until said compartment reaches the picking position, the number of components wasted is even further reduced. This is due to the fact that the compartments containing the exposed components are covered by the separating means both when the tape guide with the carrier tape is mounted in the component mounting machine, and when the tape guide with the carrier tape is located away from the machine. This is accomplished by the feature of the carrier tape retaining means, as described above. The carrier tape retaining means is provided for retaining the carrier tape such that the carrier tape is not accidentally displaced relative the tape guide, i.e. such that the tape guide can not move along the length of the carrier tape when the carrier tape has been loaded into the tape guide and before attachment of the tape guide into, or after detachment of the tape guide from, the component mounting machine, i.e. when the tape guide with the carrier tape is located away from the component machine. Thereby, following loading of the carrier tape into the tape guide, the tape guide is prevented from being accidentally removed from, or accidentally moved along the length of, the carrier tape. This ensures that when loading the carrier tape into the tape guide, the desired position of the carrier tape relative the component mounting machine, and its parts, can be chosen. The chosen position is then maintained until the carrier tape is released from the tape guide.
According to the most preferred embodiment of the invention, the carrier tape retaining means comprises a friction coupling, said friction coupling exerting a friction power upon the carrier tape sufficient to prevent the carrier tape from being accidentally displaced relative the tape guide. However, according to this embodiment, the friction power exerted by the coupling is insufficient to detrimentally affect the feeding action of the carrier tape into the component mounting machine, said feeding action being performed by feeding means provided in the component mounting machine. Therefore, there is no need for manipulating the friction coupling for enabling feeding of the carrier tape. Preferably, the friction coupling comprises a flexible support spring, provided in the tape guide underneath the carrier tape, and a counter support. The carrier tape is inserted between the support spring and counter support and is thereby held in place by the friction power. When removing the carrier tape from the tape guide, the carrier tape can simply be pulled out from the tape guide.
Additionally, using a flexible support spring for holding the carrier tape in place, brings the further advantage of stabilising the carrier tape, i.e. vibrations of the carrier tape when feeding the tape towards the picking position is greatly reduced, which reduces the risk of components being dislocated within their compartments. Furthermore, by using a flexible support spring for retaining the carrier tape, there will be no need for having movable parts in the tape guide, which facilitates the manufacturing of the tape guide and, hence, reduces production costs for producing the tape guide.
According to an embodiment, the exposure means constitutes part of the carrier tape retaining means. Preferably, the separating means is used for providing the counter support comprised in the friction coupling embodiment of the carrier tape retaining means described above. Thereby, no additional element is required as said counter support.
According to an embodiment of the present invention, the release of the carrier tape can either be performed manually, preferably only when the tape guide and the carrier tape are located away from the component mounting machine, or automatically, preferably when the tape guide with the carrier tape is mounted in the machine. According to said embodiment the carrier tape retaining means comprises a pivoted lever, preferably spring-loaded. The lever is at one end provided with a locking pin that, when in use, engages a hole of the carrier tape, thereby keeping the carrier tape at a position suitable for engagement by the feeding device. The lever is manually released during loading and unloading of the carrier tape into/from the tape guide, when the tape guide is located away from the component mounting machine, and is automatically released when loading the tape guide, with or without a component tape, into the component mounting machine. The automatic release of the lever is achieved by the other end of the lever, opposite the end provided with the locking pin, being engaged by a part of the component mounting machine during the attachment of the tape guide into the machine.
As described above, the carrier tape retaining means ensures that the carrier tape is held in place relative the tape guide after removal from the component mounting machine, unless manually released. Thus, the tape guide may remain attached to the carrier tape between the unloading and reloading of the tape guide. Thereby, there will be no additional removal of the cover tape from the carrier tape when reloading a carrier tape into the machine, and, hence, there will be no waste of components due to reloading of a carrier tape that already has been partly used. This will reduce the overall costs for the manufacturing process.
According to an embodiment of the present invention, the body of the tape guide is formed by an elongated open-ended profile with opposing elongated walls, and a base connecting said elongated walls. The walls are provided with the above described guiding means for guiding the carrier tape. The base is provided with an opening for receiving feeding means, provided in the component mounting machine or in an intermediate device attached to the machine, e.g. a tape magazine, for engagement with the carrier tape by protrusion through the opening and engagement with feeding holes provided on the carrier tape. Thus, the tape guide does not comprise any feeding mechanisms at all, which significantly reduces the manufacturing costs for the tape guide.
After the carrier tape has been loaded into the tape guide, the tape guide can be connected to the tape reel, according to an embodiment of the invention, by arranging holding means on the tape guide for attachment of the tape guide to a tape reel. Thereby, the carrier tape reel can not be unrolled, and the tape reel can easily be stored together with the tape guide for quick mounting into a component mounting machine.
According to an embodiment of the invention, the holding means comprises a clip for attachment of the tape guide to a tape reel. According to an alternative embodiment, the holding means comprises a piece of Velcro(copyright) on the tape guide engaging a corresponding piece of Velcro(copyright) provided on the tape reel. As realised by a person skilled in the art, various types of holding means are contemplated without extending beyond the scope of the present invention.
According to an aspect of the present invention, a tape magazine is provided for reception of at least one tape guide according to the invention, the magazine being provided with the corresponding locking means interacting with the locking means provided on the tape guide, said corresponding locking means otherwise being provided in the component mounting machine, as described above. The tape magazine is further provided with means for receiving at least one tape reel provided with a carrier tape, such that said reception can be performed when the carrier tape of the tape reel is loaded into the tape guide, and feeding means for feeding the carrier tape(s) towards the picking position. The tape magazine is coupled to, or mounted or attached to, the component mounting machine and forms an intermediate device between the tape guide, with the loaded carrier tape and tape reel, and the component mounting machine, and feeds the components to their respective picking position within the machine.
For the purposes of the interaction between the tape guide and the component mounting machine, as described in the previous paragraphs referring to the present invention, xe2x80x9ccomponent mounting machinexe2x80x9d can in these paragraphs be replaced by xe2x80x9ctape magazinexe2x80x9d.
Further details and aspects of the invention will become apparent from the following detailed description of embodiments of the invention, reference being made to the accompanying drawings, wherein like reference numerals refer to similar parts throughout.